1. Field of Invention
The present invention relates to improved protective structures for vehicular engine parts that generate substantial heat and vibration during engine operation, such as exhaust manifolds. More particularly, the invention relates to protective heat shields applied to such parts for insulating the parts with respect to other components within an engine compartment of a vehicle.
2. Description of the Prior Art
In today""s modern vehicles, the exhaust manifolds of internal combustion engines can reach under-the-hood temperatures in the neighborhood of 1600 degrees Fahrenheit. Such high temperatures can create significant risks of damage to electronic components nested under the hood. Thus protection is warranted, and has been provided via use of heat shields designed to cover up, and hence to insulate, exhaust manifolds and other heat generating components. In some cases, the shields have been effective to reduce measured temperature levels to within a range of 300 degrees Fahrenheit, along with substantial commensurate reductions in noise levels. Typical heat shields, however, comprise several metal layers that have sharp edges prone to creating cuts in the hands and/or fingers of installers of such structures.
In addition, many conventional heat shields are comprised of at least two entirely separate half-portions with at least three sets of detached capscrews and nuts required to hold the assembled half-portions together. In the typical production line, a minimum of two or three people are employed for such assembly of the heat shields, particularly when larger under the hood components, such as exhaust manifolds, are involved. Moreover, working with separate capscrew and nut components occasionally exacerbates nuisance factors in an assembly line environment, particularly in cases where several people are working together in close quarters.
The present invention provides an improved insulated heat shield for engine components, such as exhaust manifolds of engines. In the described embodiment, a heat shield is formed of two contiguous halves to form a unitary structure adapted to be secured together via bolted connections to and about an engine manifold.
In the described embodiment, the shield includes three layers; an outer layer of metal to provide overall structural integrity, a center layer of an insulation material to isolate heat and to dampen noise, and an inner layer adjacent the shielded component for reflecting heat back to the shielded component.
In the described embodiment, the edges of the metal layers are folded over to avoid cutting hands and/or fingers of installers or assemblers, or even under-the-hood wiring and hose structures. In addition, the folded over edges provide reinforcement of the heat shield structure to minimize vibration, and to thus maximize service life. In addition, the capscrews and nuts are rotatably mounted firmly on integral grommets provided in the heat shield structure to permit a single installer to assemble the heat shield without requirement of assistance from fellow workers.